In general, vibration models having various shapes have been suggested and put to practical use in construction machines, excavators, vibro rippers, and vehicles. Vibration characteristics generally include load mass dependency and input dependency. Load mass dependency is related to a curvature of load-displacement characteristics, and input dependency is related to hysteresis of the load-displacement characteristics.
For example, metal springs, air springs, rubber for protection against dust, or shock absorbers are used in dust removing units that prevent vibration generated from vibration generation sources such as construction machines, excavator hydraulic breakers, or vibro rippers from being transferred to a boom or car body. When soft springs are used in dust removing units, a resonance point is moved to a low frequency but vibration transmissibility is increased. When transmissibility of the resonance point is reduced, a damping ratio of a damper needs to be increased. However, when the damping ratio of the damper is increased, transmissibility of a high frequency is increased. Thus, performance of a conventional passive vibration model is limited. Active control is required for optimization in all conditions.
Korean Registration Patent No. 10-0331934 discloses a vibration mechanism using a magnetic spring, and Korean Patent Registration No. 0161564 discloses a hydraulic breaker damping device.